Most plastic materials are highly flammable and this limits their use in many products, especially building materials. Federal, state and municipal fire codes require building materials to pass different tests before they can be used for construction new buildings or the renovation of existing structures. This has significantly reduced the use of plastic products in the construction industry. Numerous attempts have been made to reduce the flammability of plastic products by adding different additives that have fire retardant or fire resistance characteristics. However, none of these attempts has produced a fire resistant plastic composition that can be easily processed and used as a substitute for non-fire resistant plastic formulations.
Flame retardants are materials that inhibit or resist the spread of fire. Brominated flame retardants (BFRs) is the designated name for a group of brominated organic substances that have an inhibitory effect on the ignition of combustible organic materials. BFRs are commonly used in electronic products as a means of reducing the flammability of the product and they are also use in clothes and furniture. The electronics industry accounts for the greatest consumption of BFRs. In computers, BFRs are used in four main applications: in printed circuit boards, in components such as connectors, in plastic covers, and in cables. BFRs are also used in a multitude of products, including plastic covers of television sets, carpets, paints, upholstery, and domestic appliances. BFRs have such a widespread number of applications because they are incredibly effective at fire prevention. In addition to reducing the likelihood that an article will ignite, brominated flame retardants hinder the spread of the fire.
Polybrominated diphenyl ether (PBDE) is a flame-retardant sub-family of the brominated flame-retardant group. Among the group of polybrominated diphenyl ethers used as flame-retardants, the fully brominated diphenyl ether, decabromodiphenyl ether (decaBDE), is the most commonly used. PBDEs have been used in a wide array of household products, including fabrics, furniture, and electronics. There are three main types, referred to as penta, octa and deca for the number of bromine atoms in the molecule. However, PBDEs, like other BFR's, are not aways completely compatible with plastic materials, such as polyolefins, and this has limited their use. Accordingly, ther is a need for a composition that includes PBDEs and different polyolefins, particularly, polypropylene.
Like most other plastic materials polypropylene and materials formed from polypropylene are flammable. Most materials containing polypropylene will also degrade over time when exposed to ultra violet (UV) light. Therefore, there is a need for polypropylene compositions that can be used to form materials which have a high flame retardance or fire resistance and are not subject to degradation when exposed to UV light. The present invention addresses both of these problems by forming compositions containing fire retardant PBDEs that are compatible with polyolefins.